<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>mission18</title>
	<style type="text/css">
		.squard{
			display: inline-block;
			width:40px;
			height: 40px;
			background: #e9605e;
			color: white;
			text-align: center;
			line-height: 40px;
			margin: 10px;
		}
	</style>
</head>
<body>
	<input type="text">
	<button id="left-input">左侧入</button>
	<button id="right-input">右侧入</button>

	<button id="left-output">左侧出</button>
	<button id="right-output">右侧出</button>
	<div id="show-number"></div>
	<script type="text/javascript" src = "task.js"></script>
</body>
</html>